1. Field of the Invention
The present invention relates to an electromechanical conversion element, a vibration actuator, a vibration actuator driving device, a lens barrel and a camera.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. Hei 9-103082 proposes the technique of adjusting an electrostatic capacitance value to a specified value by connecting an external capacitor to a piezoelectric element.
However, the electrostatic capacitance value of the piezoelectric element for driving an ultrasonic motor generally has a positive temperature coefficient (the electrostatic capacitance value increases with increasing temperature), and will vary with environmental temperature and the like.
Therefore, the vibration characteristics of the piezoelectric element will also vary with environmental temperature and the like. For example, when the piezoelectric element is used as the driving source of a lens drive motor, it may be difficult to obtain the desired drive characteristics.